Documenting Use Cases Data Dictionary for the Use

Documenting Use Cases • Data Dictionary for the Use Cases • Data Dictionary contains 1. the composition of data used within a Use Case in terms of data elements 2. the units, types, sample values, and other notes relevant for the data elements 1 Power. Point Presentation for Dennis, Wixom & Tegardem Systems Analysis and Design Copyright 2001 © John Wiley & Sons, Inc. All rights reserved.

Data Structure Notation Data structures contain data elements symbol meaning = is composed of + and () optional [] select one of several choices | alternative choices in [] {} repetition, or iteration 2 Power. Point Presentation for Dennis, Wixom & Tegardem Systems Analysis and Design Copyright 2001 © John Wiley & Sons, Inc. All rights reserved.

Data Elements Info General data element name, aliases definition Format Type, Length, Picture, Measurement unit Control Source access and update authorizations security 3 Power. Point Presentation for Dennis, Wixom & Tegardem Systems Analysis and Design Copyright 2001 © John Wiley & Sons, Inc. All rights reserved.

Data Elements Info usage info value range frequency of access Relationships parent structures data flows Processes Reports forms and screens 4 Power. Point Presentation for Dennis, Wixom & Tegardem Systems Analysis and Design Copyright 2001 © John Wiley & Sons, Inc. All rights reserved.

Example for Data Structure Notation order = customer-name + shipping-address + 1{item}10 customer-type = [govt|private|non-profit] 5 Power. Point Presentation for Dennis, Wixom & Tegardem Systems Analysis and Design Copyright 2001 © John Wiley & Sons, Inc. All rights reserved.

Structural Modeling Chapter 7 Slide 6 Power. Point Presentation for Dennis, Wixom & Tegarden Systems Analysis and Design Copyright 2001 © John Wiley & Sons, Inc. All rights reserved.

Key Ideas A structural or conceptual model describes the structure of the data that supports the business processes in an organization. . The structure of data used in the system is represented through CRD cards, class diagrams, and object diagrams. 7 Power. Point Presentation for Dennis, Wixom & Tegardem Systems Analysis and Design Copyright 2001 © John Wiley & Sons, Inc. All rights reserved.

Purpose of Structural Models Reduce the “semantic gap” between the real world and the world of software Create a vocabulary for analysts and users Represent things, ideas, and concepts of importance in the application domain 8 Power. Point Presentation for Dennis, Wixom & Tegardem Systems Analysis and Design Copyright 2001 © John Wiley & Sons, Inc. All rights reserved.

Classes Templates for creating instances or objects Concrete Abstract Typical examples: Application domain, user interface, data structure, file structure, operating environment, document, and multimedia classes 9 Power. Point Presentation for Dennis, Wixom & Tegardem Systems Analysis and Design Copyright 2001 © John Wiley & Sons, Inc. All rights reserved.

Attributes Units of information relevant to the description of the class Only attributes important to the task should be included 10 Power. Point Presentation for Dennis, Wixom & Tegardem Systems Analysis and Design Copyright 2001 © John Wiley & Sons, Inc. All rights reserved.

Operations Action that instances/objects can take Focus on relevant problemspecific operations (at this point) 11 Power. Point Presentation for Dennis, Wixom & Tegardem Systems Analysis and Design Copyright 2001 © John Wiley & Sons, Inc. All rights reserved.

Relationships Generalization Enables inheritance of attributes and operations Aggregation Relates parts to wholes Association Miscellaneous relationships between classes 12 Power. Point Presentation for Dennis, Wixom & Tegardem Systems Analysis and Design Copyright 2001 © John Wiley & Sons, Inc. All rights reserved.

CLASS-RESPONSIBILITYCOLLABORATION CARDS Slide 13 Power. Point Presentation for Dennis, Wixom & Tegarden Systems Analysis and Design Copyright 2001 © John Wiley & Sons, Inc. All rights reserved.

Responsibilities and Collaborations Responsibilities Knowing Doing Collaboration Objects working together to service a request 14 Power. Point Presentation for Dennis, Wixom & Tegardem Systems Analysis and Design Copyright 2001 © John Wiley & Sons, Inc. All rights reserved.

A CRC Card Front: Class name: ID: Type: Description: Responsibilities: Collaborators: Back: Attributes: Relationships: Generalization (a-kind-of): Aggregation (has-parts): Other Associations: 15 Power. Point Presentation for Dennis, Wixom & Tegardem Systems Analysis and Design Copyright 2001 © John Wiley & Sons, Inc. All rights reserved.

CLASS DIAGRAMS Slide 16 Power. Point Presentation for Dennis, Wixom & Tegarden Systems Analysis and Design Copyright 2001 © John Wiley & Sons, Inc. All rights reserved.

Example Class Diagram 17 Power. Point Presentation for Dennis, Wixom & Tegardem Systems Analysis and Design Copyright 2001 © John Wiley & Sons, Inc. All rights reserved.

Class Diagram Syntax A CLASS Class 1 -attribute +operation () Attribute name/ derived attribute name AN ATTRIBUTE AN OPERATION operation name () AN ASSOCIATION 18 1. . * 0. . 1 ______verb phrase____ Power. Point Presentation for Dennis, Wixom & Tegardem Systems Analysis and Design Copyright 2001 © John Wiley & Sons, Inc. All rights reserved.

More on Attributes Derived attributes /age, for example can be calculated from birth date and current date Visibility Public Protected Private 19 Power. Point Presentation for Dennis, Wixom & Tegardem Systems Analysis and Design Copyright 2001 © John Wiley & Sons, Inc. All rights reserved.

More on Operations Constructor Creates object Query Makes information about state available Update Changes values of some or all attributes 20 Power. Point Presentation for Dennis, Wixom & Tegardem Systems Analysis and Design Copyright 2001 © John Wiley & Sons, Inc. All rights reserved.

More on Relationships Class can be related to itself (role) Multiplicity Exactly one, zero or more, one or more, zero or one, specified range, multiple disjoint ranges Association class 21 Power. Point Presentation for Dennis, Wixom & Tegardem Systems Analysis and Design Copyright 2001 © John Wiley & Sons, Inc. All rights reserved.

Object Diagrams 22 Power. Point Presentation for Dennis, Wixom & Tegardem Systems Analysis and Design Copyright 2001 © John Wiley & Sons, Inc. All rights reserved.

Summary CRC cards capture the essential elements of a class. Class and object diagrams show the underlying structure of an objectoriented system. Constructing the structural model is an iterative process involving: textual analysis, brainstorming objects, role playing, creating the diagrams, and incorporating useful patterns. 23 Power. Point Presentation for Dennis, Wixom & Tegardem Systems Analysis and Design Copyright 2001 © John Wiley & Sons, Inc. All rights reserved.

Problem for Structural Modeling: Chapter 7, Mini. Case 2, page 213. 24 Power. Point Presentation for Dennis, Wixom & Tegardem Systems Analysis and Design Copyright 2001 © John Wiley & Sons, Inc. All rights reserved.